An ultrasound machine is configured for developing new modes for obtaining images or other useful information from ultrasound signals. The machine has a data processor configured to control a transmit circuit to generate ultrasound signals. Echo signals are received and digitized to yield RF data that is stored in a memory accessible to the data processor. A user can operate design mode application software to change the manner in which the RF data is processed to yield images or other useful information. New modes can be developed rapidly. The data processor may comprise a conventional personal computer equipped with suitable interfaces. An ultrasound machine may include and use a floating point processor for processing ultrasound signals.